Common Points of Engine Failure

[tweiss3]

I've been reading (in my never ending strive to accumulate information) of a few engine failures, and I thought (i searched) that it would be nice to have a single thread about the different types of engine failures. So far the few I have had are as follows.

1)Bearing failure for the e-shaft
- usually oil related, sometimes overheating and over reving
2)Apex seal failure, chipping, scoring
- detonation the cause?
3)Carbon build up causing the rotors to become un-ballanced
-it happens, but can be prevented mostly, also the water cleaning can fix carbon already built up
4)Seal/compression can be lost
-side seals, seal springs loose springyness, improper clearances, wear on the housings, apex seals, cold ass weather doesn't ever help, oil starvation (OMP failure or lack of proper ratio of premix)

Are there any others? Anyone care to go further into what causes these failures, and what can be done to prevent these? I'm just wondering, and of course, knowing failure points helps your maitnence, and your tuning/building knowledge.